1: 1.) NaBH4 / 1.) methanol, -15 deg C, 30 min; 2.) acetic acid-water-THF (3:1:1), 45 deg C, 3 h 2: 93 percent / pyridinium p-toluenesulphonate / CH2Cl2 / 3 h / Ambient temperature 3: 1.) NaCH2SOCH3 / 1.) DMSO, r.t., 30 min; 2.) DMSO, 45 deg C, 22 h 4: 79 percent / acetic acid; H2O; tetrahydrofuran / 3 h / 45 °C View Scheme

Multi-step reaction with 3 steps 1: 1.) lithium aluminium hydride; 2.) 10percent NaOH / 1.) ether, 1.5 H; 2.) water, 1 h2: 2.67 g / NaOAc, pyridinium chlorochromate / CH2Cl2 / 3 h / Ambient temperature3: 1.) NaH / 1.) THF, r.t., 30 min; 2.) THF, r.t., 30 min